Miss Gaynor Evans

Hello, I will be visiting Japan in March for the first time and I need to buy a 7 day Japan Rail Pass. I am confused when I should activate this? I arrive in Japan on 29/03/25 and will be travelling from Haneda airport into Tokyo. I will be in Tokyo until 01/04/25 when I will then travel to Kyoto and want to travel from there to Osaka, Nara and Hiroshima. I will then return to Tokyo on 05/04/25 until 07/04/25. So my question is, as I can only buy the pass for 7 days, is it better for me to buy it to start as soon as I arrive on 29/03/25 to use around Tokyo and to get me from the airport or is it better to buy it to start on 30 or 31/03/25 so that I can use it for the other cities in Japan?